A lot of dryers sell you on how hygienic they are since you never have to touch them. However, a recent study suggests that paper towels are in fact the more hygienic choice.

The study, published by the Mayo Clinic last August, is a review of 12 other studies published since 1970. The result? Paper towels help fight more bacteria, thanks to friction.

The differences in bacterial numbers after drying with air dryers and paper towels could be due to other factors rather than the percentage of dryness alone. Friction can dislodge microorganisms from the skin surface during both hand washing and drying. Antimicrobial agents in soaps have too little contact time to have bactericidal effects during a single use or with sporadic washings, making friction the most important element in hand drying.

That doesn't mean you should swear off all air dryers—sometimes there just isn't any paper around. But if you're somewhere hygiene is particularly important, like a hospital or a school, then choosing to dry your hands with paper towels could be a great extra precaution.